diff --git a/libc/bionic/__fwrite_chk.cpp b/libc/bionic/__fwrite_chk.cpp
new file mode 100644
index 0000000..2af13d6
--- /dev/null
+++ b/libc/bionic/__fwrite_chk.cpp
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#undef _FORTIFY_SOURCE
+#include <stdio.h>
+#include <sys/cdefs.h>
+#include "private/libc_logging.h"
+
+extern "C" size_t __fwrite_chk(const void * __restrict buf, size_t size, size_t count,
+                               FILE * __restrict stream, size_t buf_size) {
+  size_t total;
+  if (__predict_false(__size_mul_overflow(size, count, &total))) {
+    // overflow: trigger the error path in fwrite
+    return fwrite(buf, size, count, stream);
+  }
+
+  if (__predict_false(total > buf_size)) {
+    __fortify_chk_fail("fwrite: prevented read past end of buffer", 0);
+  }
+
+  return fwrite(buf, size, count, stream);
+}